John Oliver explains why the police-shooting problem is even bigger than we realize

But Oliver points out that this is more than just a matter of police departments having a "few bad apples."

"There are nearly 18,000 different police departments in America, and they are not great at reporting or sharing data,” Oliver said.

In the segment, there's video of FBI Director James Comey stating that there are no records kept in the country of how many people have been shot by police.

Because of that, Oliver points to one researcher who gathered information on police shootings via Google alerts. His research found that out of 1,000 police shootings since 2005, only 77 officers have been charged with murder or manslaughter and to date only 26 have been convicted.

Only 26 convictions seems extremely low. Oliver shows how that's possible with less than objective investigations by internal affairs and even some officers deleting past incidents from their official police files. Or if an officer has an incident at a department that will hurt them in the future, they may simply resign and move to another police department. This is done so much that the practice has a name in law enforcement: "gypsy cops."

The segment is an incredible deep dive into the complexities of the topic.